The location of a user device may be relevant to a transaction associated with the user device. For example, a software company might be interested in licensing a software program to be executed only on Personal Computers (PCs) that are located on a particular university campus. Similarly, a video game company might charge a first price for a Compact Disc Read Only Memory (CD-ROM) containing a video game if the game is to be played in person's home but charge a second price if the game is to be played in a business establishment. As another example, a movie company might sell a Digital Versatile Disc (DVD) containing a movie on the condition that the movie only be viewed in a particular country.
One way of determining the location of a user device is to ask a user to provide information, such as his or her ZIP code or home address. However, some users may find such a process annoying or mistakenly provide incorrect information. Moreover, some users may intentionally provide false information (e.g., in order to obtain a lower price).
It is also known that a user device may be marked in some way with location information. For example, a cookie file containing location information may be stored at the user device via a Web browser program. Such an approach may also involve a third-party database, such as a database that associates a user's location with an identifier that is hard-wired into the user device, such as an identifier that is incorporated in the INTEL® PENTIUM® III processor. This approach, however, may rely on information that was initially provided by a user and may not be correct when, for example, the user has moved his or her PC to a new home. Other user's may be reluctant to provide any type of location information at all (e.g., to a third-party) for privacy reasons.
Many DVD players are given region codes that mark where they were sold. Some DVD movies are marked with a region-encoding so that players from a different region will refuse to play them. Such region encoding systems are very constraining since the set of regions is determined in advance and can not be finely tailored to the particular content or economic transaction of interest.
Other solutions involve the use of online license servers that issue authentication tokens on the basis of IP addresses and other information that implicitly identifies the location of the user. Such systems not only involve the use of dedicated license servers that must be maintained at some expense, but also introduce serious privacy concerns due to the monitoring of the usage patterns of software. Such privacy concerns become even more serious when it is content that is access controlled. The record of connections to the license server in such cases can be used to determine who is reading what and when.
Moreover, it may be difficult for a user device to determine location information without receiving the information from a user. For example, a user device that incorporates a traditional Global Positioning System (GPS) receiver may be unable to properly determine location information when indoors. Furthermore, traditional GPS receivers involve much specialized hardware and are often expensive, making them impractical for use in mass-marked consumer oriented devices.